20 CALIFORNIA ACADEMY OF SCIENCES. 



Arionta arrosa Gould. (No. 26.) 



I have lately seen several more specimens of the small 

 form mentioned in Bull, 7, p. 372, labeled "A. arrosa, Ala- 

 meda Co." by the finder, and probably from near the same 

 locality. It is therefore not a chance straggler there, though 

 rare and local only in or near " KedAvood Canon," just as it 

 is found near the redwoods Avest and north of the bay. The 

 size is less than that of coast specimens, but larger than 

 some from Napa County, and though about equal to some 

 of the varieties of A. calif or niensis, differs in seven whorls 

 and other characters. Connecting links between the two 

 are not found yet, though var. holderiana east of the bay 

 comes very near some of the forms of var.? exarata north 

 of it. 



A. (californiensis) ram n sa Gould. (No. 32.) 



This form shows an ability to withstand droughts and 

 heat, great than any other of the large banded species of 

 this coas^ On the east shore of San Francisco Bay it is 

 sometimes found in colonies along the sides of little gullies, 

 washed out by springs which almost entirely dry up in sum- 

 mer, and where no rocks or trees shelter them, the largest 

 vegetation being a c irse grass about five feet high, and 

 annual herbage. Th( may be found in these stations tor- 

 pid during about four dry months, partly concealed in 

 slight cavities, and are remarkable for thickness of shell, 

 derived from the fossiliferous soil of tbe pliocene terraces 

 jrom which the springs flow. They are not found along the 

 permanent streams near by, where rocks and shade abound, 

 and where the thin form No ''•O is rather common. 



A. anachoreta Biuney. 



In the synopsis (Proc. Cal. Acad., iii, 338.), I classed this 

 bandless shell as perhaps identical with a form found near 

 lat. 42°, and still of uncertain specific standing; but since I 

 have collected near the place where Thomson found the 



